160 THE GENUS PERIPATUS. 



Further, the dorsal ridges are interrupted by thin and sharp, 

 less coloured lines, which are somewhat diagonally arranged, and 

 divide the ridges into lozenge-shaped areas (vide figs. 1 and 10), 



The antennae are ringed and taper slightly till near their 

 termination, where they present a slight enlargement. 



The rings consist essentially of a number of coalesced primary 

 papillae, and are, therefore, beset by a number of spines like 

 those of the primary papillae. They are more deeply pigmented 

 than the rest of the antenna. 



The free end of the antenna is covered by a cap of tissue like 

 that of the rings. It is followed by four or more rings placed 

 close together on the terminal enlargement. There appears to 

 be about thirty rings on the antennae of all adults of this 

 species. But they are difficult to count, and a number of small 

 rings occur, between them, which are not included in the thirty. 



The antennae are prolongations of the dorso-lateral parts of 

 the anterior end of the body. 



The eyes are paired and are situated at the roots of the 

 antennae on the dorso-lateral parts of the head. Each is placed 

 on the side of a protuberance which is continued as the an- 

 tenna, and each presents the appearance of a small crystalline 

 ball inserted on the skin in this region. 



The rings of papillae on that part of the head from which 

 the antennae arise lose their transverse arrangement. They 

 are arranged nearly concentrically to the antennal rings, and 

 have a straight course forwards between the antennae. 



The oral papillae are placed at the sides of the head. They 

 are attached ventro-laterally on each side of the lips. The 

 duct of the slime gland opens through their free end. They 

 possess two main rings of projecting tissue, which are especially 

 pigmented on the dorsal side ; and their extremities are covered 

 by papillae irregularly arranged (vide description of oral papilla 

 of New Zealand species, p. 175). 



The Buccal Cavity. — The buccal cavity has the form of 

 a fairly deep pit, of a longitudinal oval form, placed on the 

 ventral surface of the head, and surrounded by a tumid lip. 



The lip is covered by a soft skin, in which are numerous 



